Archbishop Desmond Tutu, who turned 80 on Friday, helped bring down apartheid and shape South African society as the voice of the nation's conscience, preaching love, forgiveness and racial integration.
Even after the fall of the whites-only regime, he never shied away from shining a spotlight on modern South Africa's failings.
When President Jacob Zuma's government failed to grant a visa to the Dalai Lama in time for the exiled Tibetan spiritual leader to attend his birthday celebrations, Tutu accused him of kowtowing to China and forgetting the values of the liberation struggle.
"One was deeply distressed that the government which came into power because oppression and injustice had been gotten rid of - and therefore it would be a government that would have welcomed everybody - that they should have done this," Tutu told AFP in an interview.
Despite the seriousness of his cause, Tutu brings to all his endeavours a playfulness, quick to crack jokes - often directed at himself - and always ready to skip, dance and laugh uproariously in public.
It was Tutu who first baptised South Africa the "rainbow nation" at the first all-race elections in 1994.
In 1996 - two years after Nelson Mandela became South Africa's first black president - he retired as archbishop of Cape Town to head up the Truth and Reconciliation Commission.
For 30 months, the commission lifted the lid on the horrors of apartheid by investigating atrocities. At one of its first hearings, Tutu broke down and sobbed as a disabled victim described his torture by the security forces.
Born in the small town of Klerksdorp, about an hour's drive west of Johannesburg, on 7 October 1931, his family could not afford to send him to university, and Tutu instead trained as a teacher on a government scholarship.
After a short stint as a teacher, his anger over the inferior education offered black children prompted him to become a priest instead.
"It wasn't for very highfalutin ideals that I became a priest," he said in a biography. "It was almost by default."
"I couldn't go to medical school... The easiest option was going to theological college."
Tutu was ordained at the age of 30 and lived in South Africa, Britain and Lesotho before being appointed the first black archbishop of Cape Town in 1986.
He used his status to advocate international sanctions against apartheid South Africa as a means to force the government to bring about change.
He believed firmly in the reconciliation of black and white South Africans and said at the first all-race elections in 1994: "I am walking on clouds. It is an incredible feeling, like falling in love. We South Africans are going to be the rainbow people of the world."
Mandela is a great admirer of Tutu and has described him as "a man who had inspired an entire nation with his words and his courage, who had revived the people's hope during the darkest of times."
But such is their relationship that Tutu felt free to chastise Mandela for living openly with Graca Machel before their marriage in 1998.
Never a member of the ruling African National Congress, Tutu challenged authority both in government and in the Church.
He spoke out against former president Thabo Mbeki's denialism of the Aids epidemic, and lashed the ruling party for trying to muzzle a Truth Commission report in October 1998.
"I didn't struggle in order to remove one set of those who thought they were tin gods and replace them with others who are tempted to think they are," he said.
Tutu has also apologised to homosexuals for the suffering the Anglican Church's teachings has caused them.
"I want to say sorry to you and all the others who have been made to suffer so horribly. Sometimes the Bible says these things are unnatural. But, I ask, unnatural to whom?"
Some of his sharpest barbs were directed at Zimbabwe's President Robert Mugabe, calling him a "caricature of an African dictator". The veteran Zimbabwean president in turn called him "an evil little bishop".
Tutu was diagnosed with prostate cancer in 1997 and underwent repeated treatments.
He married his wife Leah in 1955 and they had four children.